The objectives of the NWACTU are to perform comprehensive analyses of virologic and immunologic events during HIV infection by systematic patient sampling and detailed laboratory studies in order to evaluate innovative therapies of HIV infection and its complications. The specific aims are relevant for many patients and reflect the aims of the AACTG. The aims include the study of novel HIV treatment strategies and agents; the treatment response of HIV in latent reservoirs; the impact of viral and host factors and treatment strategies on long-term and clinical and virologic outcomes; viral dynamic models for evaluating new therapies and guiding treatment strategies; treatment and prophylaxis discontinuation following HIV-treatment induced immune reconstitution; metabolic complications of HIV disease and antiretroviral therapy; the treatment of neuropathy and HIV-associated dementia; the mechanism of immune restoration; the validation of the immunologic determinants of clinical and virologic benefit medicated by therapy; enhancement of restoration of appropriate immune function by application of immune-based therapies; and long-term treatment strategies. The NWACTU is a collaborative effort of three Chicago institutions: Northwestern University Medical School, Rush-Presbyterian-St. Luke's Medical Center, and Cook County Hospital. The ACTU offers several components and capabilities and proposes to use them to make contributions to AIDS research. These components include: a consortium of experienced virologists, clinicians, immunologists, and molecular biologists with complementary areas of expertise; the ability to enroll and retain a large, diverse study population; a history of working together as evidenced by joint publications and investigator-initiated grants; the presence of a quality-controlled laboratory for processing, tracking, and storing specimens; participation in other NIH-directed AIDS research; an organizational plan for administrative, clinical and laboratory endeavors; and the provision of scientific and administrative leadership to the Adult AIDS Clinical Trials Group. These characteristics, and the basic science and clinical capabilities of the group, should allow the NWACTU to support a significant proportion of the specific aims and objectives of the AACTG.